This disclosure relates to a method of repairing a gas turbine engine component.
Gas turbine engines are a primary source of power for aircraft propulsion. The main components of a gas turbine engine include a compressor section, a combustor section and a turbine section. Each of these sections includes a plurality of components that may require repair after use in a particular environment. For example, both the compressor section and the turbine section include alternating rows of rotor blades supported on a rotor assembly and stator blades supported on a stator assembly by a plurality of stator shrouds. The severe operating conditions experienced by these components may cause surface deterioration of the components, such as stator shroud wear, for example. In some instances, the components within the turbine section may be exposed to service temperatures above 3,000° F. The relatively high cost of gas turbine engine components due to their respective materials necessitates repair of the components to attempt to extend their service life.
Repair of gas turbine engine components by brazing is known. This process typically involves applying braze material to the base alloy of the component followed by furnace operation. After the braze material is diffused into the base alloy by the furnace operation, the excess material is removed via a machining operation. For example, the excess material may be removed by milling, facing, drilling or grinding. The machining operation can expose surface pores on the gas turbine engine component under repair. The pores are caused by incomplete braze flow during the diffusion cycle of the vacuum furnace operation. This is referred to as “post machining porosity.” If the pores are large enough, they may be deemed unacceptable and the relatively expensive gas turbine engine component must be removed from service and replaced by a new component.